凶手的英文：
assailant
murderer
assassin

参考例句：

The killer was merciless.
凶手残酷无情。

The mass murderer was given three concurrent life sentences.
那个屠杀群众的凶手被同时判处并执行三个无期徒刑。

The witness deposed to having seen the murderer.
证人做证说曾经看见这个凶手。

The assassin was hustled to safekeeping.
凶手迅即被押走，予以保护性拘留。

Swanson persuaded Hubley to work undercover to capture the killer.
斯旺森说服赫布利去做卧底以便将凶手抓获。

The line appears to be a reference to a cherokee folk tale, whose recounting may shed light on the mind of the sniper
也许，这个古老的切罗基族传说，能够为我们揭开连环杀人凶手神秘的面纱。

retributive acts against the killers
对凶手的惩罚

The killer stabbed him with a knife/stabbed a knife into him.
凶手用刀刺他.

The police has caught the murderer alive.
警方已将凶手缉拿归案。

Are you a student or a thug?
你是学生还是凶手?

assailant是什么意思：
n. 攻击者

Did you get a make on the assailant?
你得知有关攻击者的资料了吗？

He scuffled with an assailant.
他和一个进攻者扭打起来。

Assailed by worries,doubts,fears,etc
饱受烦恼,疑惑,恐惧等折磨.

murderer是什么意思：
n. 谋杀；谋杀案

a mass murderer
杀戮众多的人

That was a quadruple murder.
那是一次四尸命案。

He was charged with murder of the first degree murder.
他被控告一级谋杀罪.

assassin是什么意思：
n. 刺客

The assassin kicked up a shine.
刺客引起了大骚动。

The man was pinked by an assassin.
他被刺客射伤了。

The fact is that he was assassinated and not suicided.
事实是他遭暗杀而不是自杀。